Coccoloba-associated xerocomoid boletes (Boletaceae) from the Caribbean and Mexico: Tropicoboletus ruborculus gen. et comb. nov., revision of Xerocomus coccolobae, phylogenetic assessment of Singerocomus guadelupae comb. nov., and type studies of Xerocomus caeruleonigrescens, X. cuneipes, and X. pseudoboletinus var. pini-caribaeae.

Only two -associated xerocomoid boletes with smooth basidiospores are currently known from the Dominican Republic, namely and . A multilocus phylogenetic analysis of four gene markers (ITS, LSU, , ) reveals that . forms an autonomous clade in the corresponding to a novel genus, which is introduced here as gen. nov., whereas is confirmed as a member of s. str. is sister to subfamily in the combined / -wide analysis. Accurate morphological descriptions of the two species based on well-annotated samples are provided, accompanied by color photographs of fresh specimens in habitat and line drawings of their main anatomical features. The holotype collections of . and . were successfully sequenced and re-examined anatomically. The distribution range of comb. nov. is extended from the original locality in Puerto Rico to the Dominican Republic and Mexico where its presence is reported for the first time. Similarly, the Dominican collections of . represent the first documented occurrence of this species for the Island of Hispaniola. Based on molecular and morphological evidence, we conclude that the Belizean species is conspecific with . and is therefore reduced into synonymy. In addition, the holotypes of , , and var. were microscopically re-studied, although their exact taxonomic placement remains unresolved in the absence of any phylogenetic inference. Molecular investigation of a paratype of resulted in a conspecificity with the recently described from Brazil, extending the biogeographic coverage of to the Caribbean. Accordingly, the new combination is proposed and . is synonymized. Finally, a putative novel s. str. species is discovered from the Dominican Republic but not formally described for the time being due to the paucity of material available.